A Scheme Interpreter

Part Two: A Datum Parser

Complete the implementation of a Scheme-style S-Expression parser, using the provided Java code. The grammar describing each datum is a subset of the syntax specified in the Revised^6 Report on the Algorithmic Language Scheme, Section 4.3 (Datum Syntax).

The subset only allows for the lexeme datum values specified in the TokenType enum, together with some of the list datum rules, including dotted notation and basic quotes. 

Datum ::= LexemeDatum | CompoundDatum
LexemeDatum ::= Boolean | Number | Character | String | Symbol
Symbol ::= Identifier
CompoundDatum ::= List
List ::= ( {Datum} )
       | [ {Datum} ]
       | ( [Datum] . Datum )
       | [ [Datum] . Datum ]
       | Abbreviation
Abbreviation ::= ' Datum

When the end-of-file is reached, your parser should return null.

Details